This is an application for partial support of the Gordon Conference entitled Muscle: Excitation/Contraction Coupling, which will be held at Waterville Valley, New Hampshire, June 14 - 19, 2009. This conference, which is the only national or international meeting with a primary focus on excitation-contraction coupling (ECC) in skeletal muscle, began in 1970 and has met every three years since. The overall goal is to increase our understanding of the link between electrical excitation and contraction of muscle, and of the roles of calcium in normal muscle function and in muscle disease. The specific aims of the 2009 conference are to convene 175 total participants, including 31 speakers in 9 sessions, with session chairs providing an introduction to each session, facilitating discussion, and highlighting controversies and important, unanswered questions. The topics of the sessions will include the ultrastructural and molecular basis for ECC, the movements of calcium during ECC, alterations in calcium dynamics that contribute to, or result from, muscle diseases and fatigue, and the role of calcium signals in the development, physiological adaptation and aging of muscle. The significance of the conference is that many of the issues of importance to ECC are also important in other tissues, and that the cellular systems underlying ECC are oftern involved in the development of pathophysiological states. The conference will foster new research because it brings together a spectrum of speakers with interests ranging from the biophysics and structure of ion channels (originally muscle and ion channels were part of a single Gordon conference), to transcriptional regulation, to muscle diseases as clinical entities. The health relatedness of the conference is that inherited human diseases of skeletal and cardiac muscle result from mutations of the proteins involved in ECC, and that calcium signaling is critical for the response of muscle to use/disuse and for its repair after injury.